Electronic controllers are used in increasing numbers in the automotive field (for example motor controllers, anti-lock brake systems, airbags, etc.). The development of battery packs with an associated battery management system (BMS) is necessary for electrically driven vehicles. A BMS comprises controllers with software for monitoring the battery functionality. Depending on the customer's requirements or available installation spaces, the topologies of battery packs are very varied in relation to the number of cells, modules, sensors, etc.
Typical BMSs ensure the safe and reliable function of the cells and packs. They monitor and control currents, voltages, temperatures, insulating resistance and other variables for the cells and the battery pack as a whole. Using said variables, management functions can be realized which increase the service life, the reliability and the safety of the battery system.
A BMS consists of a multiplicity of controllers on which individual software functionalities run. Depending on the number of cells, the number of sensors and the distribution of the battery modules in different installation spaces in the vehicle, a controller topology emerges which has a main controller and a plurality of subordinate sensor controllers for acquiring the measured data directly at the individual battery modules. The measured data can be, for example, voltages, temperatures, currents, etc. The acquired data is exchanged between the controllers via a communication bus, for example a controller area network (CAN).
By using a communication bus with a defined bandwidth, the total data traffic which can be transported on the bus in a particular time is limited. A narrow maximum bandwidth reduces the probability of disturbances, for example by undesired electrical or electromagnetic effects. By using a high number of battery modules and associated sensor controllers, all measured data must be very frequently communicated on the bus to the main controller. The measurement frequency is thus limited by the bandwidth on the bus and the number of battery modules.
A method and a device for processing signals from battery sensors is known from published application DE 10 2004 046 621 A1, wherein, for two measured variables, in particular for current and voltage, a sliding average is formed in each case from two successive measured values of a measured variable, wherein the Nth and the N+1th value of the first measured variable is weighted with different factors from the Nth and N+1th value of the second measured variable.